[PATCH v9 03/96] mm/debug: Factor PagePoisoned out of __dump_page

From: Matthew Wilcox (Oracle)
Date: Wed May 05 2021 - 11:10:01 EST


Move the PagePoisoned test into dump_page(). Skip the hex print
for poisoned pages -- we know they're full of ffffffff. Move the
reason printing from __dump_page() to dump_page().

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
mm/debug.c | 25 +++++++------------------
1 file changed, 7 insertions(+), 18 deletions(-)

diff --git a/mm/debug.c b/mm/debug.c
index 84cdcd0f7bd3..e73fe0a8ec3d 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -42,11 +42,10 @@ const struct trace_print_flags vmaflag_names[] = {
{0, NULL}
};

-static void __dump_page(struct page *page, const char *reason)
+static void __dump_page(struct page *page)
{
struct page *head = compound_head(page);
struct address_space *mapping;
- bool page_poisoned = PagePoisoned(page);
bool compound = PageCompound(page);
/*
* Accessing the pageblock without the zone lock. It could change to
@@ -58,16 +57,6 @@ static void __dump_page(struct page *page, const char *reason)
int mapcount;
char *type = "";

- /*
- * If struct page is poisoned don't access Page*() functions as that
- * leads to recursive loop. Page*() check for poisoned pages, and calls
- * dump_page() when detected.
- */
- if (page_poisoned) {
- pr_warn("page:%px is uninitialized and poisoned", page);
- goto hex_only;
- }
-
if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
/*
* Corrupt page, so we cannot call page_mapping. Instead, do a
@@ -173,8 +162,6 @@ static void __dump_page(struct page *page, const char *reason)

pr_warn("%sflags: %#lx(%pGp)%s\n", type, head->flags, &head->flags,
page_cma ? " CMA" : "");
-
-hex_only:
print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
sizeof(unsigned long), page,
sizeof(struct page), false);
@@ -182,14 +169,16 @@ static void __dump_page(struct page *page, const char *reason)
print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
sizeof(unsigned long), head,
sizeof(struct page), false);
-
- if (reason)
- pr_warn("page dumped because: %s\n", reason);
}

void dump_page(struct page *page, const char *reason)
{
- __dump_page(page, reason);
+ if (PagePoisoned(page))
+ pr_warn("page:%p is uninitialized and poisoned", page);
+ else
+ __dump_page(page);
+ if (reason)
+ pr_warn("page dumped because: %s\n", reason);
dump_page_owner(page);
}
EXPORT_SYMBOL(dump_page);
--
2.30.2